You may be burning more calories than you thought when you walk. Scientists at Southern Methodist University in Dallas, Texas, have discovered that because of a limited amount of data collected in the past, people may be underestimating how many calories they burn when they go for a walk.

In the past, researchers calculated walking energy expenditure with the help of data from just a limited number of people. This particular equation ran under the assumption that "one size fits all." With that said, this is clearly not always the case.

That's why the researchers in this latest study developed a new equation that's about four times more accurate than the original equation, which predicted too few calories burned in about 97 percent of cases.

"Our new equation is formulated to apply regardless of the height, weight and speed of the walker," said Lindsay Ludlow, one of the researchers. "And it's appreciably more accurate."

But how did they create this equation in the first place? The researchers compiled a database using walking metabolism data that was available in existing scientific literature. This allowed them to evaluate leading equations for walking on level ground.

"Burning calories is of major importance to health, fitness and the body's physiological status," said Peter Weyand, a researcher in the SMU Locomotor Laboratory of biomechanics. "But it hasn't been really clear just how accurate the existing standards are under level conditions because previous assessments by other researchers were more limited in scope."

The more accurate estimations could help those who need to count calories accurately, such as those who are training for an athletic competition or carrying out a military objective. This, in turn, could help researchers design ways to help people, especially military personnel, avoid stress or fatigue while in the field.

The findings aren't just good for athletes and military personnel, though. They also could be important with the rise of fitness watches. With the new equation, these mobile devices can more accurately predict how many calories a person wearing one happens to be burning. This could help people monitor their body's status and potentially help them lose weight.

The study was published in the March 1 issue of the Journal of Applied Physiology.